Sound-producer.



L. SAVART.

SOUND PRODUCER.

APPLICATION FILED JAN. 13, I915.

1,168,96'Y Patented Jan. 18, 1916.

fizven bm:

Lama's Sawwnfi THE COLUMBIA PLAryoGnAPH 60.. WASHINGTON, D. c.

1 TD s'rns PA LOUIS savannor PARIS, mines. a

SOUND-TRODUCER.

Specification of Letters Patent.

Patented J an. 18, 1916.

Application filedlanuary 13,1915. Sei'ia1No.2,05 2.

T 0 all whom it may concern Be it known that I, LOUIS Samar, a citi-T zen of the French Republic, residing at Paris, France, have invented certain new and useful Improvements in Sound-Pro; ducers, of which the, following is a spec fi cation. I The ma or1ty of horns used on motor cars generally comprise reeds which break up into regular waves the current of' air blown therethrough. It is found in practice that the sound emitted by such horns is discontinuous or interrupted. This is due to the fact thatthe current of air has not a definite and constant pressure, so I that pulsations or excesses of pressure are produced in the which a reed is used. To thatend, instead.

of connecting the sound tube or the amplifying bell mouth directly to the reed, the conduit terminating at the same is controlled by a vibrating tongue extended accordingly, and the whole is inclosed in an air tight box which has no connection with the atmosphere.

In the accompanying drawing-Figure 1 shows diagrammatically an arrangement of the system according to this invention. Fig. 2 shows in longitudinal section and in crosssection, and Fig. 3 in longitudinal section, in cross-section and in plan constructions of the sound producer, diagrammatically shown in Fig. 1.

According to this invention, the chamber 0 containing the reed, is closed in an air tight manner, and the sound is emitted through a tube 6 arranged in the said chamber 0, the inner opening of the said tube being controlled by the tongue 6 of the reed suitably extended for the purpose.

When air is blown in through the tube a, the tongue 0 of the reed is raised, thereby admitting the air into the chamber 0, there being no outlet from the chamber save that into 6, which must be reached under the tongue 6. This air exerts a pressure on the tongue 6 in opposition to the air forced into the tube a. This counter pressure is obviously less than that of the: air blown, in through the tube a, but it acts on a larger area of the tongue e as shown in Fig. 2,.

and it has a tendency to force the tongue 6 against its seat and thus close the air tube at. At the moment when the tongue 6. is brought close. to its seat there is, an equalization of these two pressures resulting in thetongue 6 remaining in a slightly raised position, thus I allowing. a direct. communication of the tubes (Land 6 for an injection of air to pro duce a sound wave in the latter tube. This state of 6(1u1lll01111111, however, is onlymomentary for thecolumn of. air passing from the chamber 0 into the tube I) is interrupted atshort intervals by the vibration of the reed e, andsince the inertia of the air column keeps the column in motion, alternate condensation and rarefactions are produced, whichcreate a sound of ,the pitch corresponding to the rate of vibration of the reed. H

Similar phenomena take place again, the

air' getting into the emission pipe I) in order to produce therein a new vibration, and so on. In the constructions llustrated, isee F igs.

;2 .and-. 3, the compressed air supply pipe a and the emission pipe 2) terminating at an amplifying bell-mouth are arranged so that their openings are concentric or in one and the same axis of symmetry, so that the orifice of one is embraced by the annular surface surrounding the orifice of the other.

In the construction shown in Fig. 2, the orifices are of rectangular shape. The air supply pipe a is provided with a flat rectangular opening and is partly surrounded by the wall of the emission pipe I) which also has a flat rectangular opening in the same plane as the opening in the air pipe a. The tongue 6 engages with these two openings. A closed chamber 0 surrounds the whole and connects the air compressor pipe on to the emission pipe I).

Where a compression bulb is utilized to produce a blast, a valve f can be used to enable the fiuid to return to the said bulb part.

In the construction shown in Fig. 3, the orifices of the pipes are circular. The air supply pipe (6 has an elbow bend, around the wall of which is arranged the annular conduit b communicating with the emission pipe I). The whole constitutes a block on which the tongue 6 is arranged so as to cover the concentric orifices of the said pipes a b. The return valve is shown at f. The device amienged ni ii a q sjd bqx The pipes engage with rubber Washersg so as to register with connections mounted by'wayof example and the shapes, material, d mensions, details and appllcations can centrally on the fixed and movable ends of the box 0." p i p I It will be seen that in the construction shown in Fig. 3, the plane of the openings with which the tongue 6 engages is arranged at a lower level than the upper plane or" ridge it of the part. The tongue 6 is consequently surrounded by a raised flange h. i

WVhen the air escapes after having raised the tongue 6, it strikes the said flange 72 which stops it. This results in an increase of pressure under the tongue which is then raised still more, until it has passed the flange it surrounding it. At this moment the air passes into the chamber 0 and acts as already described.

It will be seen further that in such a con- I struction of sound producer, the opening of the tongue 6 is effected partly. by the pressure of the air blown into the apparatus, while its closing is due in part to the counter-pressure exercised by the fluid which has passed into the closed chamber 0, it being understood that the elasticity of the tongue itself plays a certain part in each case. The periods of opening and closing determine the sound waves produced in the tube 6.

In the construction shown in Fig. 3, the sound producer arranged in the axis of the casin .ciilSfii Q j 1'e in ing l of eb nite, a.

The above constructions arev given merely vary according to circumstances, without departing from this invention.

What I claim as my invention and desire to secure by'Letters Patent is 1. In a sound producer, an air supply pipe and an emission pipe co-extensive therewith, said pipes having adjoining orifices; a vi brating tongue covering and controlling said orifices and" an air tight chamber completely surrounding the portions of" said pipes in which the adjoining orifices are formed.

2. In a sound producer, an air supply pipe and an emission pipe axially'in line, said pipes having adjoining rectangular orifices, a vibrating metal tongue controlling both said orifices, a partition located between the pipes, fand a valve in said partition for permitting the return of air from said emission pipe to said supplypipe.

In testimony'whereof I have signed my name to this'specification in th presence of wo subscriblng witn I p LOUIS SAVART,

Witnesses: Y

IIENRI ELLEIBY,

DE WrrrC. PooLn, Jr.

Copies 0'! this patent may be obtained for five cents each, by ad dress in g'the" Commissioner of Patents; 'washingtomhci 

